SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9b75e4e89380971afa7d83725277e003b147f1c2d816a9af9651c0fcb86c2268' 
  AND token = 'PeIwUnlDUQTipvbNfqxrKDMWP1YOlMPram8pGev75fM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}